1. Field of the Invention
The present invention relates to a hair dryer.
2. Description of the Related Art
In a typical hair dryer, noise is generated by rotation of an impeller arranged to blow air. U.S. Pat. No. 8,256,132 describes a hair dryer including a silencer (a silencer for a drying appliance and a silent hair dryer). The silencer is an expansion-type silencer, and is arranged on an inlet side of an impeller to reduce noise. The hair dryer includes an orifice through which outside air is sucked in, an expansion chamber (a chamber) as the silencer, and an orifice through which the air is sucked into a centrifugal turbofan. Further, for a smooth flow of air, the orifice through which the air is sucked into the impeller is arranged to have a diameter greater than that of the orifice through which the outside air is taken in. In addition, the expansion chamber is arranged to have a diameter greater than that of the orifice through which the air is sucked into the impeller.
However, regarding the hair dryer described in U.S. Pat. No. 8,256,132, focus is not placed on either the magnitude relationship between the diameters of the respective orifices, or the internal structure of the expansion chamber. Accordingly, a sufficient silencing effect is not achieved by the expansion chamber. For example, after passing through the orifice through which the outside air is sucked in, a flow of air is disturbed, resulting in increased air passage resistance. Therefore, increasing the rotation rate of the impeller to achieve a required air volume leads to increased noise. If the air passage resistance is increased as described above, a part of a silencing effect to be achieved by the expansion-type silencer is not sufficiently achieved.